The present invention pertains to a design and a method of manufacturing sputter target assemblies for magnetron sputter thin film coating processes.
Sputtering targets attached to aluminum or copper based backing plates are used to deposit thin films on substrates for semiconductor device manufacturing. These target assemblies provide mechanical and electrical attachment of the target material to the sputter apparatus, provide vacuum sealing surfaces to maintain proper chamber environment, and typically provide a path of heat removal for effective cooling of the target material during sputter deposition.
Until now, copper or aluminum backing members fulfilled these functions adequately. Recently, however, target assembly designs have increased in size, typically by 30%. During operation, traditional copper and aluminum materials do not provide enough mechanical strength to prevent excessive deformation of the target assembly which results in poor deposited film quality and may stress the target-to-backing member joint to the breaking point. Accordingly, there is a need for sputter target assemblies having increased deflection resistance with strong target-to-backing member joint strength, vacuum-capable sealing surfaces, and high heat conductivity.